Felting apparatus and method



Jan. 5, 1960 T. E. HEPPENSTALL ET AL 2,919,475

FELTINGAPPARATUSAND METHOD Filed June 15, 1953 2 Sheets-Sheet 1 I 118 JINVENTORS .ThomasEHeppens 1 -011 BY and'HrHwrLMoHei Jan. 5, 1960 T. E.HEPPENSTALL ETAL 2,919,475

FELTING APPARATUS AND METHOD Filed June 15, 1953 2 Sheets-Sheet 2 IN VEN TORS ThomasEHe e-ns fall United States Patent f FELTING APPARATUS ANDMETHOD Thomas Earl Heppenstall and Arthur L. Motte't, Longview, Wash.,assignors, by mesne assignments, to Inv,. ternati0nal Paper Company, NewYork, N.Y., a con poration of New York Application June 15, 1953, SerialNo. 361,688

' 5 Claims. (Cl. 19-155 7 This invention relates vto felting apparatusfor forming moist or dry fibrous material into a felt or mat preliminaryto pressing the mat into fiberboard. The apparatus is. applicable to thefelting of a variety of fibrous materials, but is particularlyapplicable to the felting of particles of lignocellulose such as Woodfibers, flakes, shavings, chips, or sawdust and is described herein withparticular reference to that application although no limitation isthereby intended.

In making hardboard and'other consolidated fibrous products it is commonpractice to reduce wood to the form of 'smallparticles, to mix theparticles with a resinous binder and a size, and then to form them intoa felt or mat. The latter then is consolidated to the desired densitybythe application of heat and pressure.

Inthe foregoing sequence of operation, the properties ofjh felt are ofcritical significance in determining the properties of the finalconsolidated product. If the felt is non uniform in composition,thickness or density, this non-uniformity is reflected in the finishedproduct which therefore is of an inferior grade.

it is particularly difficult to control the uniformity of a'mat feltedby the dry or moist processes from fibrous elements of irregular size,such as wood flakes, shavings .or chips because of the difiicultyinvolved in delivering them frorn theifelting apparatus inthe uniform,continuous flow which is necessary for building up a uniform,

continuous felt. In spite of this, however, it is desirable to use suchmaterials as raw materials for hardboard manufacture because of theirlow cost, abundance, and, in some cases, because of desirable propertieswhich they impart to the finished board.

It therefore is animportant object of the present invention to providefelting apparatus capable of forming dry or moistwood flakes, chips, andshavings and similar fibrous materials into a uniform felt.

It is another important object of this invention to provide feltingapparatus which will dry felt wood flakes,

chips, shavings and likematerial continuously and at a high rate.

,Another object of this invention is the provision of felting apparatuswhich will dry felt fibrous materials uniformly even though thematerials are supplied to the apparatus at a non-uniform rate.

Still another object of the present invention is the provision ofapparatus which will dry felt fibrous materials rapidly and uniformlywithout plugging of the apparatus by the fibrous materials.

I It is another object of the present invention to provide apparatus fordry felting fibrous materials which though of high capacity, is simplein construction and readily adaptable to plantoperation.

The manner in which the foregoing and other objects of this inventionare accomplished will be apparent from ice Figure 2 is a detail view inside elevation as viewed from the direction indicated by the arrows 2-2of Figure 1;

Figure 3 is a detail sectional view in side elevation illustrating thefelting head of the presently described apparatus; and

Figure 4 is a detail sectional view taken along the line 44 of Figure 1.

Generally stated, the felting apparatus of this invention comprises ahopper for receiving and transmitting a quantity of fibrous material.Feeding means communicates with the hopper for supplying the material toit at a rate which is not necessarily uniform. Stationed side by sideadjacent the outfeed end of the hopper are a pair of parallel, rotatablymounted, spaced apart, feed rolls for receiving between them materialdischarged by the hopper.

The opposed peripheral surfaces of the feed rolls are separated by adistance which is less than the thickness of the hopper. The feed rollstherefore engage the material leaving the hopper and compress it whileadvancing it toward the discharge side.

A comb roll is rotatably mounted between the feed rolls on the dischargeside in the region of compression of the fibrous material. It rotatesrelatively rapidly and combs out substantially individual fibrouselements from the compressed mass. These elements pass next todistributing means which distributes them upon receiving means, such asan endless belt where they are built up into a substantially uniformfelt. The thickness of the felt is controlled still further, however, bymeans of a levelling device which scalps or levels it to the desiredthickness. The fibrous material thus removed from the felt then mayberecycled to the hopper, if desired.

Considering the foregoing in greater detail and with particularreference to the drawings: A

Dry or moist fibrous material, such as Wood, chips,

shavings, or fibers coming, for example, from a defiberizer, a chipperor other suitable wood reducing apparatus is fed through a conduit 10into a separator 12. Thence it passes through a rotary sealing valve 14into a spout 16.

. Spout 16 has for its function the delivery of the fibrous material tothe hopper 17 of the felting apparatus in such a manner as to build upan accumulation of the material within the hopper to a uniform heightacross its width. This facilitates uniform delivery of the material fromthe hopper.

To this end the upper end of spout 16 is pivotally attached to separator12 below the rotary valve by means of pins 18. Its lower end extendswithin the upper end of the hopper so that it may oscillate therein,delivering fibrous material across the entire width of the hopper.

Accordingly spout 16 is connected to drive means which in theillustrated form comprises a slide 20 attached longitudinally to thespout through guide members 22. A pin 24 extends outwardly from theslide. It is attached to a link of the endless drive chain 26, mountedon suitably positioned sprockets and driven through a pulley wheel 28interconnected by belt 30 to a motor 32. Thus as is indicatedparticularly in Figure 2, spout 16 may be swung from side to side acrossthe width of the hopper.

Hopper 17 may be of any desired configuration, but preferably isdownwardly and outwardly flared and of substantial height to provideample storage space. This is because in normal plant operation it isdifficult to provide a uniform flow of fiber. The hopper thus afiords areservoir for storage of a substantial quantity of fibrous materialwhich then may be fed out of the hopper at a uniform rate. The dischargeend of the hopper has a thickness a (Figure 3), the significance ofwhich is discussed below.

Hopper 17 extends within housing 40 of the felting head of the apparatusto such an extent that its discharge end is immediately adjacent a pairof feed rolls 44, 46. These are stationed side by side immediately belowthe hopper for receiving the material discharged thereby in the areabetween the rolls.

The rolls are provided with spikes 48, 50 for engaging the fibrousmaterial and for carrying it into the area between the rolls. Thespacing of the spikes is such as to engage the fibrous material withoutbecoming clogged thereby, and also such as to provide a clearancedistance between the spikes as the rolls rotate.

Feed roll 44 is rotatably mounted on a shaft 52 journalled in bearings54, 56. Feed roll 46 is rotatably mounted on a shaft 58 journalled inbearings 60, 62. Bearings 54, 56 are mounted on a frame member providedwith slots, and bearings 60, 62 are similarly mounted so that theposition of the two feed rolls relative to each other may be varied asdesired.

It is to be noted that in order to have a uniform feed of fibrousmaterial, such as wood fibers, between the feed rolls 44 and 46, one ormore of several critical factors must be observed. In the first place,the diameter b, of the rolls should be substantial as compared with thethickness a of the hopper. Thus, diameter b should be at least equal to,preferably from two to eight times thickness 01. In the second place,the sidewalls of hopper 17 should extend as closely as possible to thesurfaces of rolls 44, 46. Thus the opposed surfaces of the two rollsbecome restricted continuations of the side walls of the hopper.

Also, and of particular importance, the distance separating the opposedperipheral surfaces of the two feed rolls should be substantially lessthan the thickness a of the hopper. Thus 0 should be between one-fourthand three-fourths, preferably about one-half a. This insures that theloose, fluify mass of fibers present in the hopper will be compacted toa coherent mat which can be passed at a uniform rate between the rolls.Under these conditions it will be apparent that the column of fiberwithin hopper 17 will move in the direction of the feed rolls uniformlyat substantially the same rate as the compressed column moves betweenthe rolls.

Drive means are provided for driving feed rolls 44, 46 in the feeddirection synchronously with each other at the desired rate. In theillustrated form the drive comprises a worm gear 64 keyed to shaft 52and a worm gear 66 keyed to shaft 58. These two gears are drivenrespectively by worms 68, 70 splined to a common shaft 72. This shaftcarries on one of its ends the pulley 78 connected through belt 80 topulley 82 on the variable speed motor 84. In this manner roll 44 may bedriven clockwise and roll 46 counterclockwise, as viewed in Figure 3,synchronously, but very slowly, for example, at a speed of but 1 or 2revolutions per minute.

Fibers transmitted between rolls 44, 46 are in a coherent, compressedcondition as has been indicated above. Accordingly in this conditionthey are amenable to combing for dislodging individual fibers which'maythen be dispersed and collected for subsequent processing. In theillustrated form, the combing means employed comprises a combing roll 86provided with a plurality of teeth 88 which are dimensioned and spacedto clear teeth 48, 50 on the feed rolls. The axis of the combing roll islocated well within the fiber compression area so that the teeth of theroll act upon the compressed fibers, disentangling them and combing outindividual fibers, thereby avoiding the dropping away of fibrous clumpsfrom the apparatus.

The combing roll assembly includes a shaft 90 which is journalled inbearings 92, 94. It is driven, by pulley 96 interconnected through belt98 to pulley 100 on motor 102, at a relatively high rate, for example,about 400 revolutions per minute, as compared with the slow rate ofrevolution of the feed rolls. The fibers combed out of the compressedmass by comb roll 86 then pass to distributing means having for itsfunction distribution of the fibers on a receiving means such as acontinuous belt upon which they are built in a uniform mat. Thedistributing means also serves the function of correcting for minorfluctuations in feed.

Although the distributing means may assume diverse forms such as areciprocating screen or a rapidly rotating spiked roll, in theillustrated form it comprises a foraminous cylinder, preferably a screencylinder having openings of a size suificient to pass and distribute thefibrous elements. When felting wood flakes, for example the screenopenings may be about 2 inches on a side.

The screen cylinder is driven at a suitable rate, for example, at from50 to 150 r.p.m., by a drive which in the illustrated embodimentcomprises a pulley 112 fastened to the cylinder, and driven through belt114 by gear motor 116.

The fibrous elements in substantially individual form thus are raineddown on the receiving means which preferably comprises an endlessconveyor 118. If desired, caul plates may first be placed on the surfaceof the belt. As a result, felt 122 will build up directly on the caulplates which furnish convenient support means for transferring it insections to a suitable press, wherein the caul plates also serve theirusual function.

Although the felt, as formed, is of reasonably uniform thickness, it maybe desirable to include in the apparatus suitable levelling means forlevelling or scalping it to the precise thickness desired. Such alevelling means may comprise the spiked levelling roll 124, rotatablymounted across the felt and positioned relative thereto in such a mannerthat its teeth extend into the felt an appreciable distance.

Roll 124 is driven by motor means at an appropriate rate. It ispartially enclosed by and communicates with a vacuum conduit includingthe sections 126, 128 and fan 130. This conveys away the fibrousmaterial removed by the levelling roll and preferably transports it tothe separator 12 for recycling to the felting head.

Operation The operation of the presently described felting apparatus isas follows:

Fibrous material such as wood flakes, chips, shavings,

fiber or sawdust is introduced through conduit 10 into separator 12.Thence it passes into oscillating spout 16 which distributes it acrossthe width of hopper 17. The latter stores the material and delivers itbetween a pair of spiked feed rolls 44 and 46.

The feed rolls compress the material and pass it downwardly against acomb roll 86 rotatably mounted in the region of fiber compression. Thecomb rolls comb out from the compressed mass substantially individualfibrous elements and passes them downwardly upon distributing means suchas the rotatably mounted screen cylinder 110.

The latter cylinder has for its function the distribution of the fibrouselements into a uniform flow and also of correcting for minorfluctuations in the flow of material delivered from the feed rolls. Itpasses the fibrous elements in a uniform rain down upon conveying meanssuch as the endless belt 118 carrying caul plates 120. The mat or belt122 built up upon the caul plates then is levelled by means of theleveling roll 124, the material removed by the roll being conveyed awayvia vacuum conduits 126, 128 and recycled into separator 12.

Thus it will be apparent that by the present invention we have providedfelting apparatus characterized by several significant advantages. Itmake a uniform dry or moist felt of fibrous materials. The felt isuniform in density, thickness and composition, even though suchirregular and diflicultly handleable materials as wood chips, shavingsand flakes are the subject matter of the felting operation. Theapparatus is easy to control and operate and does not plug despite thetendency of fibrous materials to cause this difiiculty. The apparatus,furthermore, is simple in construction and design and well suited forcontinuous production of dry or moist felts in large scale plantoperations.

It is to be understood that the form of our invention, herewith shownand described, is to be taken as a preferred example of the same, andthat various changes in the shape, size and arrangement of parts may beresorted to, without departing from the spirit of our invention, or thescope of the subjoined claims.

Having thus described our invention, we claim:

1. Felting apparatus for felting fibrous materials comprising a hopperfor receiving and transmitting a quantity of fibrous material, a spoutthe outfeed end of which feeds into the hopper, means for mounting thespout for oscillation with respect to the hopper, slide means stationedon the spout longitudinally thereof, a pin extending outwardly from theslide means, an endless chain adjacent the pin, means for connecting thepin to the chain, motor means connected to the chain for driving thesame at a rate calculated to oscillate the spout at a predeterminedvelocity, a pair of parallel, rotatably mounted feed rolls stationedside by side adjacent the outfeed end of the hopper for receivingbetween them material discharged thereby, the feed rolls having theiropposed peripheral surfaces separated by a distance substantially lessthan the thickness of the hopper, motor means connected to the feedrolls for driving them in the feed direction, thereby engaging thematerial discharged by the hopper and compressing it while advancing ittoward the discharge side of the feed rolls, a comb roll having anoperating diameter not substantially exceeding the space between thefeed rolls and rotatably mounted between the feed rolls at the dischargeside thereof in the region of substantially maximum compression of thefibrous material, motor means for driving the comb roll at a ratesufiicient to comb out substantially individual fibrous elements fromthe compressed mass, distributing means stationed below the comb rollfor uniformly distributing the individual fibers over an areatherebelow, and felt forming means stationed below the distributingmeans for receiving the uniformly distributed fibers and forming a felttherefrom.

2. Felting apparatus for felting fibrous materials and comprising ahopper for receiving and transmitting a quantity of fibrous material, aspout the outfeed end of which feeds into the hopper, means for mountingthe spout for oscillation with respect to the hopper, slide meansstationed on the spout longitudinally thereof, a pin extending outwardlyfrom the slide means, an endless chain adjacent the pin, means forconnecting the 7 pin to the chain, motor means connected to the chainfor driving the same at a rate calculated to oscillate the spout at apredetermined velocity, a pair of parallel, rotatably mounted feed rollsstationed side by side adjacent the outfeed end of the hopper forreceiving between them material discharged thereby, the feed rollshaving their opposed peripheral surfaces separated by a distancesubstantially less than the thickness of the hopper, motor meansconnected to the feed rolls for driving them in the feed direction,thereby engaging the material discharged by the hopper and compressingit while advancing it toward the discharge side of the feed rolls, acomb roll having an operating diameter not substantially exceeding thespace between the feed rolls and rotatably mounted between the feedrolls at the discharge side thereof in the region of substantiallymaximum compression of the fibrous material, motor means for driving thecomb roll at a rate suificient to comb out substantially individualfibrous elements from the compressed mass, a rotary screen havingopenings of a size sufficient to pass therethrough all of the fibrouselements from the fiber combing means, means for mounting the rotaryscreen below the fiber combing means for rotation to uniformlydistribute all of the fibrous elements from the fiber combing means, andfelt forming means below the rotary screen for receiving the uniformlydistributed fibrous elements and forming a felt therefrom.

3. Felting apparatus for felting fibrous materials, comprising a hopperfor receiving fibrous material and having a horizontally elongatedoutfeed end, a pair of spaced power driven feed rolls mounted below andadjacent the outfeed end of the hopper for rotation on horizontal axesextending substantially parallel to the elongated outfeed end of thehopper, the spacing between the adjacent surfaces of the feed rollsbeing substantially less than the horizontal width of the outfeed end ofthe hopper, whereby to compress the fibrous material receivedtherebetween from the hopper, a comb roll having an operating diameternot substantially exceeding the said spacing between the feed rolls androtatably mounted between the 1 feed rolls at the discharge side thereofin the region of substantially maximum compression of the fibrousmaterial, power drive means connected to the comb roll for rotating thelatter at a speed substantially greater than that of the feed rolls tocomb out substantially individual fibrous elements from the compressedmaterial, and means positioned below the feed rolls and comb roll forreceiving the combed fibrous elements and forming a felt therefrom.

4. A method of producing substantially individual fibrous elements fromfibrous lignocellulose material, comprising supplying bulk fibrouslignocellulose material, subjecting the bulk fibrous lignocellulosematerial to a compressive force, and subjecting the compressed mass offibrous lignocellulose material to a combing action while in the area ofsubstantially maximum compression whereby to comb out substantiallyindividual fibrous elements from the compressed mass.

5. A method of felting fibrous lignocellulose material, comprisingsupplying a continuous feed of bulk fibrous lignocellulose material,subjecting the bulk fibrous lignocellulose material to a compressiveforce, subjecting the compressed mass of fibrous lignocellulose materialto a combing action while in the area of substantially maximumcompression whereby to comb out substantially individual fibrouselements from the compressed mass, and distributing the fibrous elementsuniformly over an area to form a uniform felt.

References Cited in the file of this patent UNITED STATES PATENTS Re.23,044 Brooks Oct. 19, 1948 1,336,402 Weiss Apr. 6, 1920 1,510,236Moussner et al Sept. 30, 1924 1,812,108 McCullough June 30, 19312,068,587 Aldrich Jan. 19, 1937 2,635,301 Schubert et a1. Apr. 21, 19532,653,353 Herrmann Sept. 29, 1953 2,746,096 Baxter et al. May 22, 19562,816,327 Hunter et al. Dec. 17, 1957

